Boredom driven Harry Potter Meme

Ok hyenas - I'm really bored here at work. Since I've been listening to the Harry Potter books on MP3 from start to finish (I'm just starting the Half Blood Prince), I was thinking about how you would rate the 7 books, and why. Rate them with #1 being the best to #7 being the worst.

( Spoilers for all 7 books ahoy )